PCF8820U Philips Semiconductors, PCF8820U Datasheet - Page 6

• Manufacturer Part Number: PCF8820U
• Description: 67 x 101 Grey-scale/ECB colour dot matrix LCD driver
• Manufacturer: Philips Semiconductors

Philips Semiconductors
6.2
6.2.1
Row driver outputs (R0 to R66) are the outputs for the LCD
row drive signals. They should be connected directly to the
67 rows of the LCD. If less than 67 rows are required, the
unused outputs must be left open-circuit.
6.2.2
Column driver outputs (C0 to C100) are the outputs for the
LCD column drive signals. They should be connected
directly to the 101 columns of the LCD. If less than
101 columns are required, the unused column outputs
must be left open-circuit.
6.2.3
The ground supply rails (V
connected together. V
V
6.2.4
The supply voltage rails (V
connected together when the same supply is used for both
the logic circuits and for the voltage multiplier. When the
circuits are fed separately, V
connected to the same supply.
6.2.5
V
voltage generator.
6.2.6
V
multiplier and must be connected to V
6.2.7
V
voltage generator which supplies the LCD outputs. The
voltage on pad V
If V
connected to pad V
If V
must be connected to pad V
voltage must be applied after applying V
removed before or when removing V
recommended that an external supply voltage is applied
after leaving the reset state. The external supply voltage
can stay applied in the Power-down mode.
2000 Dec 07
SS2
LCDOUT
LCDSENSE
LCD
67 101 Grey-scale/ECB colour dot matrix
LCD driver
LCD
LCD
is related to V
is the supply voltage on pad V
Pad functions
is generated internally, pad V
is supplied externally, the external supply voltage
R
C
G
S
V
V
S
is the output of the voltage multiplier of the high
UPPLY VOLTAGE
OLTAGE MULTIPLIER OUTPUT
OLTAGE MULTIPLIER REGULATION INPUT
UPPLY VOLTAGE OF BIAS VOLTAGE GENERATOR
OW DRIVER OUTPUTS
OLUMN DRIVER OUTPUTS
ROUND SUPPLY
is the regulation input of the high voltage
LCDIN
DD2
LCDIN
SS1
.
must not be lower than V
.
is related to V
SS1
DD1
LCDIN
DD2
, V
and V
and V
DD2
. An external supply
LCDIN
SS2
DD1
LCDOUT
and V
LCDOUT
DD3
DD1
) must be
DD1
(see Fig.25). It is
for the bias
must be
, and it must be
DD3
and V
must be
.
) must be
DD1
DD3
.
;
6
When an external supply voltage is used, pads V
V
together. However, if pads V
both connected to pad V
can be reduced under the following conditions:
6.2.8
The LCD intermediate bias voltages (V
which are applied to the LCD columns and rows are
present on these pads for test purposes. They must be left
open-circuit in the application.
6.2.9
SDA_IN is the serial data input from the I
6.2.10
SDA_OUT is the serial data output (data, acknowledge)
for the I
pad SDA_IN makes the SDA line fully I
Not connecting pad SDA_IN to pad SDA_OUT allows the
device to be used in applications in which the acknowledge
bit is not required. In Chip-On-Glass (COG) applications, it
is sometimes beneficial not to connect pad SDA_OUT to
pad SDA_IN. This is because in COG applications where
the track resistance from pad SDA_OUT to the system
SDA line is significant, a voltage divider is created by the
bus pull-up resistor and the Indium Tin Oxide (ITO) track
resistance. This divider could prevent the PCF8820 from
asserting a valid logic 0 level during an acknowledge
cycle.
In COG applications, where the acknowledge cycle is
required, the track resistance from the pad SDA_OUT to
the system SDA line must be minimized to guarantee a
valid LOW-level.
6.2.11
SCL is the serial clock input from the I
LCDSENSE
The output of V
(see Table 8)
The HIGH voltage programming range is selected by
setting bit PRS = 1, the maximum voltage multiplier on
factor 8 and the V
value (see Table 2).
2
C-bus. Connecting pad SDA_OUT to
LCD
S
S
S
ERIAL DATA INPUT
ERIAL DATA OUTPUT
ERIAL CLOCK INPUT
and V
INTERMEDIATE BIAS VOLTAGES
LCDOUT
LCDOUT
LCD
control register on the maximum
LCDIN
do not have to be connected
is set to high-impedance
LCDSENSE
, the current consumption
Product specification
2
and V
2
2
C-bus.
C-bus compatible.
, V
PCF8820
2
C-bus.
3
, V
LCDOUT
4
and V
LCDIN
are
5
,
)